docs: def dict2str(self, d: Dict, joiner: str) -> str:
          """
          Convert dict to str as input for tokenizer
  
          Args:
              d (dict): dict for converting
              joiner (str): join the elements using this string to separate them.
  
          Returns: the value of the dict as a string
  
          """
          result = str()
          for key in d:
              result = result + str(key) + " : "
              if isinstance(d[key], list):
                  result = result + self.list2str(d[key], joiner) + joiner
              elif isinstance(d[key], dict):
                  result = result + self.dict2str(d[key], joiner) + joiner
              elif d[key]:
                  result = result + str(d[key]) + joiner
          return result